Map index error

Terraform
1

I’m getting error, when trying to reference my subnet ids for route table association.

Blockquote#
Public Subnet
resource “aws_subnet” “public-subnet” {
for_each = var.public_subnet_cidr_map_of_maps
vpc_id = [for my_vpc in aws_vpc.vpc_network_map : my_vpc.id if my_vpc.tags.Name == “Management-VPC”][0]
availability_zone = each.value.availability_zone
cidr_block = each.value.cidr

tags = {
Name = each.value.name
}
}

#using map to iterate
output J_vpc_list {
value = {for my_vpc in aws_subnet.public-subnet : my_vpc.tags.Name => my_vpc.id}
}

#doing associtaion:

#Assign the public route table to the public Subnet

resource “aws_route_table_association” “public-rt-association” {
for_each = {for my_vpc in aws_subnet.public-subnet : my_vpc.tags.Name => my_vpc.id}
subnet_id = aws_subnet.public-subnet[each.key]
route_table_id = aws_route_table.public-rt.id
}

Blockquote

I’m getting following error:

Blockquote
Error: Invalid index

on network.tf line 125, in resource “aws_route_table_association” “public-rt-association”:
125: subnet_id = aws_subnet.public-subnet[each.value]
|----------------
| aws_subnet.public-subnet is object with 3 attributes
| each.value is “subnet-01d53d016846ac98c”

The given key does not identify an element in this collection value.

Error: Invalid index

on network.tf line 125, in resource “aws_route_table_association” “public-rt-association”:
125: subnet_id = aws_subnet.public-subnet[each.value]
|----------------
| aws_subnet.public-subnet is object with 3 attributes
| each.value is “subnet-04781855551cf83f9”

The given key does not identify an element in this collection value.

Error: Invalid index

on network.tf line 125, in resource “aws_route_table_association” “public-rt-association”:
125: subnet_id = aws_subnet.public-subnet[each.value]
|----------------
| aws_subnet.public-subnet is object with 3 attributes
| each.value is “subnet-0e65784f2b1b0f719”

The given key does not identify an element in this collection value.

Blockquote

Can you please explain what I’m doing wrong.

Also, what if I want only subnet id 2 to be associated to route table? How can I do this?

2

Hello naqvisn!
In the snippet you enclosed, the subnet_id is referencing each.key but the output of the errors are referencing each.value. Can you confirm which you are trying to use?

In addition, could you attach a redacted example of the var.public_subnet_cidr_map_of_maps? It will help to ensure that we have the schema correct when you are doing for_each.

Thank you!